Airburst and inertia impact fuze assembly for munitions

ABSTRACT

A fuze assembly for a bomb is shown. This assembly includes a firing device in which a squib is detonated within a chamber to drive a firing pin against a detonator charge to detonate a bomb. The squib is exploded by any suitable means such as a proximity sensor to obtain an airburst explosion of the bomb. An inertia ball, in the same chamber, causes the firing pin to strike the detonator charge upon impact of the bomb on a target, in the event the squib does not perform this function.

United States Patent 1151 3,636,879 Benner 1 Jan. 25, 1972 54 AIRBURST AND INERTIA IMPACT 3,151,557 l0/l964 Evanoffet al ..102 70 FUZE ASSEMBLY FOR MUNITIONS [72] Inventor: David E. Benner, Webster, Ind. [73] Assignee: Avco Corporation, Richmond, Ind. 221 Filed: Nov. 6, 1969 [21] Appl. No.: 874,526

FOREIGN PATENTS OR APPLICATIONS 35,474 8/1929 France 102/70 Primary ExaminerSamuel F einberg A!torney-Charles M. Hogan and Eugene C. Goodale [5 7] ABSTRACT 52 us. c1. ..102/70.2 R, 102/78 A We assembly a is This assembly includes a s 1 1 1m. c1 ..F42b 5/08 firing device in which a Squib is hemmed within a chamber to 58 Field Of Search 102/70, 70.2, 76, 7s drive a firing P against a detohator charge to detonate a bomb. The squib is exploded by any suitable means such as a [56] References Cited proximity sensor to obtain an airburst explosion of the bomb. An inertia ball, in the same chamber, causes the firing pin to UNITED STATES PATENTS strike the detonator charge upon impact of the bomb on a tar- 2,931,299 4/1960 Sokolowski ..102/70.2 the event the Sqmb pe'fmm funcmn' 3 ,279,3 1 8 V388 et al 1 Claims 2 Drawing Figures 2,834,292 5/1958 Viasmensky l02/70.2

AIRBURST AND INERTIA IMPACT FUZE ASSEMBLY FOR MUNITIONS The present invention relates to improvements in fuze assemblies for detonating bombs and similar munitions and more particularly to improved firing devices for such assemblies.

For greatest efi'ectiveness in certain tactical operations it is desirable to obtain an airburst wherein a bomb is detonated at a relatively low altitude rather than upon impact. Additionally, it is highly desirable to ensure detonation of the bomb upon impact in the event the airburst mechanism fails to function properly. Not only does this give assurance that the bomb will have at least some effectiveness, such a feature also minimizes the problems associated with unexploded bombs, commonly referenced as duds.

Accordingly, one object of the invention is to provide an improved, simple and reliable device for airburst detonation of bombs.

Another object of the invention is to accomplish the above ends and provide improved means for ensuring detonation of the bomb upon impact, in the even of a failure in the airburst firing mechanism, no matter how remote the chances of such a failure might be.

Another highly desirable characteristic of fuze assemblies is economical, multifunction capability. A highly effective fuze assembly is disclosed in U.S. Pat. No. 3,511,184, issued May 12, 1970, to R. E. Bowers, and of common assignment with the present application. The fuze assembly of the referenced application assures detonation at low angles of impact as well as being adapted for use with bombs having retardation fins which are deployed to retard the bomb after its release from an aircraft to ensure safe separation from the aircraft before detonation.

A further and more specific object of the invention is to economically add an airburst capability for the fuze assembly of the referenced application.

In its broader aspects the invention comprises exploding a charge into a chamber. The force of this charge, through piston means, drives a firing pin against a detonator charge, which, in turn, detonates the bomb.

More specific aspects include forming the chamber cylindri cally, with the piston means in the form of a piston member connected to the firing pin. The charge is a squib mounted at one end of the chamber and is exploded through the use of any suitable means such as a proximity sensor. To provide for impact detonation of the bomb, an inertia ball is enclosed in the chamber. Upon impact, this ball drives the firing pin against the detonator charge, in the event the squib has not performed this function.

The above and other related objects and features of the invention will be apparent from a reading of the following description of the disclosure found in the accompanying drawing and the novelty thereof pointed out in the appended claims.

In the drawing:

FIG. I is an elevation, partly in section, of a fuze assembly embodying the present invention; and

FIG. 2 is a view similar to FIG. 1, illustrating the firing action of the fuze assembly.

The illustrated fuze assembly comprises a frame which is mounted on the structure of a bomb (not shown), in a known fashion, in predetermined relation to the explosive charge of the bomb. A timing device 12 is mounted on the frame 10 and controls a latch arm 14. The latch arm 14 maintains a detonator holder 16 in its safe position illustrated in F IG. 1. When the timing device 12 releases the latch arm 14 from the holder 16, the holder is rotated about axis 18 to align a detonator charge 20 with a firing pin 22 as can be seen from FIG. 2.

The firing pin 22 is a component of a firing device 23 which includes a housing 24 and is threaded into the frame 10. The pin 22 is slidable in a hole in the lower end of the housing 24 and has a piston 26connected to its upper end. The housing 24 forms a cylindrical chamber 28 within which the piston 26 slides. An inertia ball 30 is disposed within chamber 28, above the piston 26. A squib 32 is mounted at the upper end of the chamber 28 in a holder 34. A spring 35 urges the piston, firing pin and inertia ball to the upper end of the chamber 28. This assembly is held together by a closure disc 36 which is engaged by a swaged lip,38 of the housing 24.

The electrical leads 40, of the squib 32,'are connected to a firing circuit 42. The firing circuit 42 may be actuated by any suitable means such as proximity detection, heat detection, timing means and the like. In the illustrative embodiment of the present invention, the firing circuit 42 is actuated by a proximity sensor 44. The sensor 44 includes an antenna 46 which may be appropriately mounted on the bomb. A battery 48 energizes the sensor 44 and firing circuit 42. The described electrical components may be of known design.

The described fuze assembly is adapted for use with a bomb having retarding fins which are deployed after release of the bomb from an aircraft. The purpose of such fins is to give the aircraft time to reach a safe distance before detonation of the bomb. When these fins are deployed, there is a substantial retardation force which results in the inertia ball 30 depressing the piston 26 to the lower end of the chamber 28. The firing pin 22 enters a relief hole 50 in the detonator holder 16. After the deceleration has diminished to a predetermined level the spring 35 returns these components to their upper positions and the detonator holder is free to move to its FIG. 2 position.

When the bomb reaches a relatively low altitude, the proximity sensor 44, in response to a signal from the antenna 46, actuates the firing circuit 42 which in turn completes an electrical connection from the battery 48 to the squib 32. The squib 32 is thus exploded to provide an explosive force within the upper end of the chamber 28 which acts against the piston 26 to displace it to the lower end of the chamber. The piston 26 drives the firing pin 22 downwardly causing it to forcibly strike the detonator charge 20 and detonate the bomb.

If, for some reason, the squib 32 fails to explode, the inertia ball 30 will cause the firing pin 22 to strike the detonator charge 20 upon impact with the target. Arrow A (FIG. 2) indicates the direction of travel of the bomb. When the bomb impacts, the inertia ball 30 will continue its travel, causing detonation of the bomb, as is more fully described in the above-referenced application showing such an inertia ball. Thus assurance is bad that the bomb will be exploded once it is released from an aircraft.

The described fuze assembly can be simply converted to serve other mission requirements. For example, the electrical circuitry can be disconnected or omitted where airburst explosion is not desired. Where the bomb does not have retarding fins, the fuze assembly is effective either upon impact or as an airburst device with little or no modification.

It will be apparent that variations of the described, preferred embodiment will occur to those skilled in the art, within the scope and spirit of the present inventive concepts. AS an example, the inertia ball 30 could have a sufi'rciently small clearance with the cylindrical wall of the chamber 28 to function as a piston means in sealing the explosive force of the squib 32 and driving the firing pin 22 against the detonator charge 20.

Having thus described the invention, what is claimed as novel and desired to be secured by Letters Patent of the United States is:

1. An airburst and inertia impact fuze assembly for bombs and like munitions comprising:

a housing formed to define a cylindrical chamber therein, said housing having a bore through one end, said bore being in communication with said chamber and in axial alignment therewith, the axes of the chamber and bore being aligned with the direction of travel of the bomb;

a firing pin mounted in said bore for slidable movement therethrough;

a piston member slidable in said chamber and connected to said firing pin;

a spring mounted between said piston member and said one end of said chamber for normally biasing said piston member away from said one end wherein said firing pin normally does not project beyond said housing;

a detonator holder formed with a relief hole and a detonator-holding cavity, said holder being adapted to be displaced from a safed position in which the relief holder is aligned with the housing bore to an armed position in which the detonator-holding cavity is in alignment with said housing bore;

a detonator charge mounted in said detonator-holding cavitiming means for maintaining said detonator holder in a safed position with the detonator charge out of alignment with the firing pin wherein axial movement of said piston and firing pin due to deceleration forces will urge said firing pin into the relief hole to maintain the fuze assembly in the safed position and prevent premature arming;

an inertia ball disposed in said chamber between said piston member and the other end of said chamber;

a squib mounted at said other end of said chamber;

a firing circuit interconnected with said squib; and

detection means responsive to given conditions interconnected with said firing circuit wherein after said detonator holder has moved to the armed position the detonator charge may be fired by energizing said squib prior to impact whereby the explosive force of the squib acting on said inertia ball and piston member drives said firing pin against said detonator charge and in the absence of energizing the squib the efiect of the energy forces acting on the inertia ball due to deceleration upon impact will cause the firing pin to be driven against the detonator charge. 

1. An airburst and inertia impact fuze assembly for bombs and like munitions comprising: a housing formed to define a cylindrical chamber therein, said housing having a bore through one end, said bore being in communication with said chamber and in axial alignment therewith, the axes of the chamber and bore being aligned with the direction of travel of the bomb; a firing pin mounted in said bore for slidable movement therethrough; a piston member slidable in said chamber and connected to said firing pin; a spring mounted between said piston member and said one end of said chamber for normally biasing said piston member away from said one end wherein said firing pin normally does not project beyond said housing; a detonator holder formed with a relief hole and a detonatorholding cavity, said holder being adapted to be displaced from a safed position in which the relief holder is aligned with the housing bore to an armed position in which the detonatorholding cavity is in alignment with said housing bore; a detonator charge mounted in said detonator-holding cavity; timing means for maintaining said detonator holder in a safed position with the detonator charge out of alignment with the firing pin wherein axial movement of said piston and firing pin due to deceleration forces will urge said firing pin into the relief hole to maintain the fuze assembly in the safed position and prevent premature arming; an inertia ball disposed in said chamber between said piston member and the other end of said chamber; a squib mounted at said other end of said chamber; a firing circuit interconnected with said squib; and detection means responsive to given conditions interconnected with said firing circuit wherein after said detonator holder has moved to the armed position the detonator charge may be fired by energizing said squib prior to impact whereby the explosive force of the squib acting on said inertia ball and piston member drives said firing pin against said detonator charge and in the absence of energizing the squib the effect of the energy forces acting on the inertia ball due to deceleration upon impact will cause the firing pin to be driven against the detonator charge. 